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Studies on Stress and the Gut:

There is “a well-established link between stress, mood disorders, and gastrointestinal disease” (1,2) and some studies have indicated that stress may be associated with the onset of certain chronic gastrointestinal problems (3,4,5,6). With this in mind, it may be of interest to note that there is a randomized, double-blind, placebo-controlled trial that investigated the effects of a combined R0175 + R0052 probiotic on symptoms relating to stress.  In this study, participants consumed a mixture of the two probiotics (consisting of a combined 3×109 CFUs) once a day for 3 weeks.  At the end of the study, the probiotic group showed significantly reduced self-reported gastrointestinal symptoms (abdominal pain and nausea/vomiting) compared to the placebo group.  There were no significant differences, however, in other stress-related physical or psychological symptoms between the two groups (7).  This was a relatively small study and additional studies with more participants are needed to further validate these findings.

A second randomized, double-blind, placebo-controlled study on the same mixture looked at the psychological effects of consumption for a longer period of time.  In this study, 55 participants took 3×109 CFUs of the probiotic product or a placebo for 30 days.  Psychological distress was measured via three different surveys and a urine cortisol test.  Median scores on two of those surveys were significantly improved in the probiotic group compared to placebo at the end of the study.  Changes in subscores relating to depression, anger-hostility, and anxiety, and the physical symptoms of stress were particularly pronounced.  Urine cortisol levels also decreased in the probiotic group over the course of the study while they stayed about the same in the placebo group.  Changes in Percieved Stress Scale test scores were not significantly different between the two groups.  The authors of this study point out a need for additional trials that rely on physiological markers of stress in addition to surveys.  They also touch upon the need for extended trials to look at the effects of these strains over longer periods of time (1).

While these results are compelling it should be noted that even though there is an association between stress and gastrointestinal issues a correlation has not been established between stress and specific gastrointestinal conditions.

Studies in People with IBS:

There are not currently any published scientific studies on the effects of Bifidobacterium longum R0175 alone or in combination with Lactobacillus helveticus R0052 in people with IBS.

Other Studies Relating to the Gut:

Additional studies investigating the effects of Bifidobacterium longum R0175 on gut pathogens and ulcerative colitis use unique multistrain probiotic mixtures or prebiotic/probiotic combinations (8,9,10).  Because the effects of these mixtures may be due to the synergistic action of their components caution should be taken in assuming that R00175 alone or that R00175 combined with just R0052 will have these same effects.


  1. Messaoudi M, et al. Assessment of psychotropic-like properties of a probiotic formulation (Lactobacillus helveticus R0052 and Bifidobacterium longum R0175) in rats and human subjects. Brit J of Nutr. 2011;105(5):755-764. doi:10.1017/S0007114510004319.
  2. Forsythe P, Sudo N, Dinan T, et al. Mood and gut feelings. Brain Behav Immun. 2010;24:9-16. doi:10.1016/j.bbi.2009.05.058.
  3. Lutgendorff F, Akkermans LM, Soderholm JD. The role of microbiota and probiotics in stress-induced gastrointestinal damage. Curr Mol Med. 2008;8:282-298. doi:10.2174/156652408784533779.
  4. Duffy LC, Zielezny MA, Marshall JR, et al. Relevance of major stress events as an indicator of disease activity prevalence in inflammatory bowel disease. Behav Med. 1991;17:101-110. doi:10.1080/08964289.1991.9937553.
  5. Garrett VD, Brantley PJ, Jones G, et al. The relationship between daily stress and Crohn’s disease. J Behav Med. 1991;14:87-96.
  6. Greene B and Blanchard EB. Cognitive therapy for irritable bowel syndrome. J Consult Clin Psychol. 1994;62:576-582. doi:10.1037/0022-006X.62.3.576.
  7. Diop L, Guillou S, Durand H. Probiotic food supplement reduces stress-induced gastrointestinal symptoms in volunteers: a double-blind, placebo-controlled, randomized trial. Nutr Res. 2008;28(1):1-5. doi:10.1016/j.nutres.2007.10.001.
  8. Grgov S, Tasic T, Radovanovic-Dinic B, Benedeto-Stojanov D. Can probiotics improve efficiency and safety profile of triple Helicobacter pylori eradication therapy? a prospective randomized study. Vojnosanit Pregl. 2016;73(11):1044-1049. doi:10.2298/VSP150415127G.
  9. Ten Bruggencate SJ, Girard SA, Floris-Vollenbroek EG, Bhardwaj R, Tompkins TA. The effect of a multi-strain probiotic on the resistance toward Escherichia coli challenge in a randomized placebo-controlled double-blind intervention study. Eur J Clin Nutr. 2015;69(3):385-391. doi:10.1038/ejcn.2014.238.
  10. Haskey N and Dahl WJ. Synbiotic therapy improves quality of life and reduces symptoms in pediatric ulcerative colitis. ICAN. 2009;1(2):88-93. doi:10.1177/1941406409332930.